Extract generated blob check into its own module

3 files changed, 165 insertions, 129 deletions

diff --git a/lib/linguist.rb b/lib/linguist.rb
index 36702e3..0f1b0f8 100644
--- a/lib/linguist.rb
+++ b/lib/linguist.rb
@@ -1,4 +1,5 @@
 require 'linguist/blob_helper'
+require 'linguist/generated'
 require 'linguist/language'
 require 'linguist/mime'
 require 'linguist/repository'
diff --git a/lib/linguist/blob_helper.rb b/lib/linguist/blob_helper.rb
index af0150c..d805df1 100644
--- a/lib/linguist/blob_helper.rb
+++ b/lib/linguist/blob_helper.rb
@@ -1,4 +1,5 @@
 require 'linguist/classifier'
+require 'linguist/generated'
 require 'linguist/language'
 require 'linguist/mime'
 require 'linguist/samples'
@@ -212,143 +213,16 @@ module Linguist
       lines.grep(/\S/).size
     end
 
-    # Internal: Compute average line length.
-    #
-    # Returns Integer.
-    def average_line_length
-      if lines.any?
-        lines.inject(0) { |n, l| n += l.length } / lines.length
-      else
-        0
-      end
-    end
-
     # Public: Is the blob a generated file?
     #
     # Generated source code is supressed in diffs and is ignored by
     # language statistics.
     #
-    # Requires Blob#data
-    #
-    # Includes:
-    # - XCode project XML files
-    # - Minified JavaScript
-    # - Compiled CoffeeScript
-    # - PEG.js-generated parsers
-    #
-    # Please add additional test coverage to
-    # `test/test_blob.rb#test_generated` if you make any changes.
+    # May load Blob#data
     #
     # Return true or false
     def generated?
-      if name == 'Gemfile.lock' || minified_javascript? || compiled_coffeescript? ||
-      xcode_project_file? || generated_net_docfile? || generated_parser?
-        true
-      else
-        false
-      end
-    end
-
-    # Internal: Is the blob an XCode project file?
-    #
-    # Generated if the file extension is an XCode project
-    # file extension.
-    #
-    # Returns true of false.
-    def xcode_project_file?
-      ['.xib', '.nib', '.storyboard', '.pbxproj', '.xcworkspacedata', '.xcuserstate'].include?(extname)
-    end
-
-    # Internal: Is the blob minified JS?
-    #
-    # Consider JS minified if the average line length is
-    # greater then 100c.
-    #
-    # Returns true or false.
-    def minified_javascript?
-      return unless extname == '.js'
-      average_line_length > 100
-    end
-
-    # Internal: Is the blob of JS a parser generated by PEG.js?
-    #
-    # Requires Blob#data
-    #
-    # PEG.js-generated parsers are not meant to be consumed by humans.
-    #
-    # Return true or false
-    def generated_parser?
-      return false unless extname == '.js'
-
-      # PEG.js-generated parsers include a comment near the top  of the file
-      # that marks them as such.
-      if lines[0..4].join('') =~ /^(?:[^\/]|\/[^\*])*\/\*(?:[^\*]|\*[^\/])*Generated by PEG.js/
-        return true
-      end
-
-      false
-    end
-
-    # Internal: Is the blob of JS generated by CoffeeScript?
-    #
-    # Requires Blob#data
-    #
-    # CoffeScript is meant to output JS that would be difficult to
-    # tell if it was generated or not. Look for a number of patterns
-    # output by the CS compiler.
-    #
-    # Return true or false
-    def compiled_coffeescript?
-      return false unless extname == '.js'
-
-      # CoffeeScript generated by > 1.2 include a comment on the first line
-      if lines[0] =~ /^\/\/ Generated by /
-        return true
-      end
-
-      if lines[0] == '(function() {' &&     # First line is module closure opening
-          lines[-2] == '}).call(this);' &&  # Second to last line closes module closure
-          lines[-1] == ''                   # Last line is blank
-
-        score = 0
-
-        lines.each do |line|
-          if line =~ /var /
-            # Underscored temp vars are likely to be Coffee
-            score += 1 * line.gsub(/(_fn|_i|_len|_ref|_results)/).count
-
-            # bind and extend functions are very Coffee specific
-            score += 3 * line.gsub(/(__bind|__extends|__hasProp|__indexOf|__slice)/).count
-          end
-        end
-
-        # Require a score of 3. This is fairly arbitrary. Consider
-        # tweaking later.
-        score >= 3
-      else
-        false
-      end
-    end
-
-    # Internal: Is this a generated documentation file for a .NET assembly?
-    #
-    # Requires Blob#data
-    #
-    # .NET developers often check in the XML Intellisense file along with an
-    # assembly - however, these don't have a special extension, so we have to
-    # dig into the contents to determine if it's a docfile. Luckily, these files
-    # are extremely structured, so recognizing them is easy.
-    #
-    # Returns true or false
-    def generated_net_docfile?
-      return false unless extname.downcase == ".xml"
-      return false unless lines.count > 3
-
-      # .NET Docfiles always open with <doc> and their first tag is an
-      # <assembly> tag
-      return lines[1].include?("<doc>") &&
-        lines[2].include?("<assembly>") &&
-        lines[-2].include?("</doc>")
+      @_generated ||= Generated.generated?(name, lambda { data })
     end
 
     # Public: Should the blob be indexed for searching?
diff --git a/lib/linguist/generated.rb b/lib/linguist/generated.rb
new file mode 100644
index 0000000..1b05e91
--- /dev/null
+++ b/lib/linguist/generated.rb
@@ -0,0 +1,161 @@
+module Linguist
+  class Generated
+    # Public: Is the blob a generated file?
+    #
+    # name - String filename
+    # data - String blob data. A block also maybe passed in for lazy
+    #        loading. This behavior is deprecated and you should always
+    #        pass in a String.
+    #
+    # Return true or false
+    def self.generated?(name, data)
+      new(name, data).generated?
+    end
+
+    # Internal: Initialize Generated instance
+    #
+    # name - String filename
+    # data - String blob data
+    def initialize(name, data)
+      @name = name
+      @extname = File.extname(name)
+      @_data = data
+    end
+
+    attr_reader :name, :extname
+
+    # Lazy load blob data if block was passed in.
+    #
+    # Awful, awful stuff happening here.
+    #
+    # Returns String data.
+    def data
+      @data ||= @_data.respond_to?(:call) ? @_data.call() : @_data
+    end
+
+    # Public: Get each line of data
+    #
+    # Returns an Array of lines
+    def lines
+      @lines ||= data.split("\n", -1)
+    end
+
+    # Internal: Is the blob a generated file?
+    #
+    # Generated source code is supressed in diffs and is ignored by
+    # language statistics.
+    #
+    # Please add additional test coverage to
+    # `test/test_blob.rb#test_generated` if you make any changes.
+    #
+    # Return true or false
+    def generated?
+      name == 'Gemfile.lock' ||
+        minified_javascript? ||
+        compiled_coffeescript? ||
+        xcode_project_file? ||
+        generated_net_docfile? ||
+        generated_parser?
+    end
+
+    # Internal: Is the blob an XCode project file?
+    #
+    # Generated if the file extension is an XCode project
+    # file extension.
+    #
+    # Returns true of false.
+    def xcode_project_file?
+      ['.xib', '.nib', '.storyboard', '.pbxproj', '.xcworkspacedata', '.xcuserstate'].include?(extname)
+    end
+
+    # Internal: Is the blob minified JS?
+    #
+    # Consider JS minified if the average line length is
+    # greater then 100c.
+    #
+    # Returns true or false.
+    def minified_javascript?
+      return unless extname == '.js'
+      if lines.any?
+        (lines.inject(0) { |n, l| n += l.length } / lines.length) > 100
+      else
+        false
+      end
+    end
+
+    # Internal: Is the blob of JS generated by CoffeeScript?
+    #
+    # CoffeScript is meant to output JS that would be difficult to
+    # tell if it was generated or not. Look for a number of patterns
+    # output by the CS compiler.
+    #
+    # Return true or false
+    def compiled_coffeescript?
+      return false unless extname == '.js'
+
+      # CoffeeScript generated by > 1.2 include a comment on the first line
+      if lines[0] =~ /^\/\/ Generated by /
+        return true
+      end
+
+      if lines[0] == '(function() {' &&     # First line is module closure opening
+          lines[-2] == '}).call(this);' &&  # Second to last line closes module closure
+          lines[-1] == ''                   # Last line is blank
+
+        score = 0
+
+        lines.each do |line|
+          if line =~ /var /
+            # Underscored temp vars are likely to be Coffee
+            score += 1 * line.gsub(/(_fn|_i|_len|_ref|_results)/).count
+
+            # bind and extend functions are very Coffee specific
+            score += 3 * line.gsub(/(__bind|__extends|__hasProp|__indexOf|__slice)/).count
+          end
+        end
+
+        # Require a score of 3. This is fairly arbitrary. Consider
+        # tweaking later.
+        score >= 3
+      else
+        false
+      end
+    end
+
+    # Internal: Is this a generated documentation file for a .NET assembly?
+    #
+    # .NET developers often check in the XML Intellisense file along with an
+    # assembly - however, these don't have a special extension, so we have to
+    # dig into the contents to determine if it's a docfile. Luckily, these files
+    # are extremely structured, so recognizing them is easy.
+    #
+    # Returns true or false
+    def generated_net_docfile?
+      return false unless extname.downcase == ".xml"
+      return false unless lines.count > 3
+
+      # .NET Docfiles always open with <doc> and their first tag is an
+      # <assembly> tag
+      return lines[1].include?("<doc>") &&
+        lines[2].include?("<assembly>") &&
+        lines[-2].include?("</doc>")
+    end
+
+    # Internal: Is the blob of JS a parser generated by PEG.js?
+    #
+    # PEG.js-generated parsers are not meant to be consumed by humans.
+    #
+    # Return true or false
+    def generated_parser?
+      return false unless extname == '.js'
+
+      # PEG.js-generated parsers include a comment near the top  of the file
+      # that marks them as such.
+      if lines[0..4].join('') =~ /^(?:[^\/]|\/[^\*])*\/\*(?:[^\*]|\*[^\/])*Generated by PEG.js/
+        return true
+      end
+
+      false
+    end
+  end
+end